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/*
* Copyright (C) 2000, 2001 Broadcom Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/*
* These are routines to set up and handle interrupts from the
* sb1250 general purpose timer 0. We're using the timer as a
* system clock, so we set it up to run at 100 Hz. On every
* interrupt, we update our idea of what the time of day is,
* then call do_timer() in the architecture-independent kernel
* code to do general bookkeeping (e.g. update jiffies, run
* bottom halves, etc.)
*/
#include <linux/config.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/kernel_stat.h>
#include <asm/irq.h>
#include <asm/ptrace.h>
#include <asm/addrspace.h>
#include <asm/time.h>
#include <asm/io.h>
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_int.h>
#include <asm/sibyte/sb1250_scd.h>
#define IMR_IP2_VAL K_INT_MAP_I0
#define IMR_IP3_VAL K_INT_MAP_I1
#define IMR_IP4_VAL K_INT_MAP_I2
#define SB1250_HPT_NUM 3
#define SB1250_HPT_VALUE M_SCD_TIMER_CNT /* max value */
#define SB1250_HPT_SHIFT ((sizeof(unsigned int)*8)-V_SCD_TIMER_WIDTH)
extern int sb1250_steal_irq(int irq);
static unsigned int sb1250_hpt_read(void);
static void sb1250_hpt_init(unsigned int);
static unsigned int hpt_offset;
void __init sb1250_hpt_setup(void)
{
int cpu = smp_processor_id();
if (!cpu) {
/* Setup hpt using timer #3 but do not enable irq for it */
__raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
__raw_writeq(SB1250_HPT_VALUE,
IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_INIT)));
__raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
/*
* we need to fill 32 bits, so just use the upper 23 bits and pretend
* the timer is going 512Mhz instead of 1Mhz
*/
mips_hpt_frequency = V_SCD_TIMER_FREQ << SB1250_HPT_SHIFT;
mips_hpt_init = sb1250_hpt_init;
mips_hpt_read = sb1250_hpt_read;
}
}
void sb1250_time_init(void)
{
int cpu = smp_processor_id();
int irq = K_INT_TIMER_0+cpu;
/* Only have 4 general purpose timers, and we use last one as hpt */
if (cpu > 2) {
BUG();
}
sb1250_mask_irq(cpu, irq);
/* Map the timer interrupt to ip[4] of this cpu */
__raw_writeq(IMR_IP4_VAL,
IOADDR(A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) +
(irq << 3)));
/* the general purpose timer ticks at 1 Mhz independent if the rest of the system */
/* Disable the timer and set up the count */
__raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
#ifdef CONFIG_SIMULATION
__raw_writeq((50000 / HZ) - 1,
IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
#else
__raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1,
IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
#endif
/* Set the timer running */
__raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
sb1250_unmask_irq(cpu, irq);
sb1250_steal_irq(irq);
/*
* This interrupt is "special" in that it doesn't use the request_irq
* way to hook the irq line. The timer interrupt is initialized early
* enough to make this a major pain, and it's also firing enough to
* warrant a bit of special case code. sb1250_timer_interrupt is
* called directly from irq_handler.S when IP[4] is set during an
* interrupt
*/
}
void sb1250_timer_interrupt(struct pt_regs *regs)
{
int cpu = smp_processor_id();
int irq = K_INT_TIMER_0 + cpu;
/* ACK interrupt */
____raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
if (cpu == 0) {
/*
* CPU 0 handles the global timer interrupt job
*/
ll_timer_interrupt(irq, regs);
}
else {
/*
* other CPUs should just do profiling and process accounting
*/
ll_local_timer_interrupt(irq, regs);
}
}
/*
* The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over
* again. There's no easy way to set to a specific value so store init value
* in hpt_offset and subtract each time.
*
* Note: Timer isn't full 32bits so shift it into the upper part making
* it appear to run at a higher frequency.
*/
static unsigned int sb1250_hpt_read(void)
{
unsigned int count;
count = G_SCD_TIMER_CNT(__raw_readq(IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CNT))));
count = (SB1250_HPT_VALUE - count) << SB1250_HPT_SHIFT;
return count - hpt_offset;
}
static void sb1250_hpt_init(unsigned int count)
{
hpt_offset = count;
return;
}
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